The Nissan Path

Did the tranny cooler bypass soon after I purchased the Pathy in Dec. 17. Fall of '18, no heat. Poked around & found split in plastic part on firewall. Priced replacement, couldn't afford & settled on glue job with JB Plastic weld. FLushed coolant, heat restored, repair held, life was good. In Feb. '19, the Pathy set a P0306 DTC. Couldn't afford plugs/coils change at the moment, so I added some LiquiMoly Complete Truck treatment to the gas to help plug removal go easier later. Code cleared, life was good again. I thought.

Current trip to hell began in August '19 on a 99° day. A/C was having trouble keeping up, engine temp normal, dogs slobbering on my shoulder, 3 quick run in/run out errands, then back home. Was on the way home in traffic, suddenly steam under hood, DTC light flashing, engine died. The repair on the firewall heater hose assembly had let go & dumped the coolant. Coasted less than1/2 block into an abandoned lot next to a local tire/auto shop. Replaced assembly by mechanic & got DTC P0345 on startup when I picked the Pathy up. Shut it down & went back in and got the mechanic. He told me after overheating sometimes "strange" codes are set. Sounded semi-plausible. He cleared the code, which returned the next day, but it got the white-haired old lady out of his face. I replaced the camshaft sensor myself with a Delco part from Autozone. Worked fine for a couple of weeks, until the P0301. Was planning a trip in late September, so decided to have another mechanic take a look to change the spark plugs, tubes, coils. He added a plenum gasket & valve cover gasket, but only changed the #1 coil (the only one currently setting the DTC) - said they were expensive & no need to change until they die. I wasn't happy, but... hey, he's the mechanic, right? Drove fine until I dropped my dog off for boarding, headed home to pack the Pathy for the trip. Had trouble starting, running rough. The P0306 had returned. I said many words of power and rented a car for the trip. Good thing. The mountains would have killed it.

Upon my return, I cleared the code & added the LiquiMoly again. Worked for a few days, then P0306 again. More words of power. Took it back to the mechanic & he agreed to replace the coils he omitted before. Told him to replace ALL the old coils, not just #6. He replaced only #6.
Ran OK (but not quite right... minor vibration/low growl under driver's seat; something jangling under driver's seat on idle) for 3 days. On a routine trip to town, it set a P0300, then P0430. Barely got up over the overpass & limped home with flashers on. Noted a "hot" odor (not coolant).

It usually starts well, no issues until it warms up, then trouble ensues.
It's now at a third mechanic's shop (since Monday). The guy is perplexed. Wants to try replacing the upstream O2 sensor & front catalytic converter. I'm semi ok with this but want to get to the heart of the problem, ie. what caused the P0430 in the first place. Since the random misfire doesn't point to a specific cylinder, he's not wild about replacing the old coils "just because..."

Suggestions, opinions?

*sorry - wrong forum. *hangs head* Please move to R51 - thanks!

But I LOVE him Jerry wrote:
*sorry - wrong forum. *hangs head* Please move to R51 - thanks!

Done! Welcome to the forum!

Welcome to the forum!
Thank you for the detailed description. someone much more qualified than me will chime in soon.

I would doubt your prior problems could trip the 0430 code. Mine threw the same code without the prior issues you described. Due to the danger of the catalytic converter material possible failing and disintegrating and being sucked back into the cylinders, I replaced both primary catalytic converters and both upstream O2 sensors. Haven’t seen the code since, at least 3 years later. Good luck!

I currently have the P0301(cylinder 1) P0744( torque converter) P0300 (cylinder misfire) codes on. Plus the typical P0430 occasionally

I have very little power uphill and limped home on my last trip. Never had this problem.
Fresh spark plugs 20k25k miles prior NGK XI Iridium

I ordered cheap amazon coils ( $70) for all 6
New plugs this time NGK Double Platinum ~$10 ea.

I will get back to this once I put it all back together and see what I get.
Im at about 156k miles.
My truck has bigger tires and heavier camping/4wheeling gear so more harsh environment.

Could it be a leaky exhaust upstream causing the P0430? Would that throw a different code?

I am not sure about the misfires. Maybe some fuel injector cleaner through the next tank, unless thats the liquidmoly you mentioned.

Update*
Did the coils and plugs. No fix on the low power under load but no check engine light. Ill have to drive it longer till I trigger it but my Pathy is not looking good. Sorry to overtake this thread just happened to have some misfire codes pop up last weekend.

Update on my situation

Bank 1 (passenger side) Primary Catalytic Converter had fallen apart and all the shrapnel had clogged the Secondary causing low power. Also when I was running tests I found out that the hotter the vehicle got the worse it ran.

I did not replace the O2 sensors yet but the Check Engine light turned off on its own.

~Update~

Sorry to overtake this thread just happened to have some misfire codes pop up last weekend.

Yes, Yes, Thupertrooper!! I think our Pathy's may be afflicted similarly! I need all the ideas I can get! Folks think I'm crazy to have bought a Nissan (I live in US Big Pickup Truck Land and I did adore my '95 Silverado which the Pathy replaced), but just like the gals on the reality show, I LOVE it and am not ready to quit on it!

SO... the latest mechanic replaced the driver's side front catalytic converter - it was trashed - looked full of rocks. Drove it home in a gullywasher of a rainstorm - thought it sounded funky, but who could hear with the rain beating down... The next day, I was right: there was an exhaust leak where the guy hadn't fitted the gasket properly. Back it went. Picked it up a couple of days later. No more exhaust leak. Everything seemed relatively hip on the drive home. Then I went out on errands and, as Thupertrooper experienced, the longer it drove, the worse things got. Threw that damnable P0300 code and hadda limp home with very little power. I suspect some downstream issues from the pieces of the upstream bad converter. I ran some live data tests on it which looked more and more funky the warmer it got & the higher the rpms, etc.

I'm stumped at this point. No mechanics whom I trust left in the area. The live data comparisons showed that the O2 sensor seems to be "lazy," which is why I wanted to replace it along with the front catalytic converter, but the guy said to "wait & see"... Didn't have to wait long to see that replacing the one front converter was insufficient! But the fuel trim numbers looked out of whack... Can post data if requested...

I keep thinking about the work that's been done thus far... When I replaced the camshaft position sensor, I used a Duralast from Autozone. Have since realized I should have gone with the Hitachi... The guy who changed the plugs did not use NGK plugs - used Irridium ones from Autozone. The coils he replaced were Masterpro.

Any & all ideas appreciated!

Addendum: A guy at the last mechanic's shop thought perhaps it was "stuck in limp mode" - What little I know about limp mode is that's a protective thing that happens when the engine is having trouble. Also wondered if I should do some kind of "relearning" song & dance routine to reset it to original values...

Alot of info to process but sounds like you have the secondary catalytic converters still. If so they could be clogged with debris from the primaries(front ones) I did bypass mine temporary till I swap the front ones entirely.

The limp mode my pathy was in was it wouldnt have power but it still ran till the point I could only do 30mph max but it was just low power not limited by the computer.

I have overheated the transmission and had gone into a govern limp mode by the computer and that is actually a limit the truck will run. Not necessarily low power just the computer wont allow it to travel any faster.

I would strongly recommend your mechanic double check the secondary cats make sure they are not clogged. Easiest way I confirmed mine were clogged I disconnected the secondaries from the primaries and pushed it back enough that it could have room to breathe out.

I did not replace the primaries yet as im waitning for the drivers side to go out also since I dont have any codes popping up even though I do have a passenger side cat out.

Keep us updated on what you find.

After mulling it all over, I took it to the local Nissan Dealership for diagnosis. The Service manager said everything was fine except the other 3 catalytic converters. He looked sheepish when he handed me an estimate to replace them with all Nissan stuff for $4074.53!!! Good thing my hair already went white, 'cause that would have done it! Didn't charge me for the DX, which I appreciated. So today, I'll cost out the replacement for the passenger side front & rear and the driver's side rear (already replaced the front driver's side). He assured me that that would solve all my problems! We'll see... will let y'all know what transpires after the replacements.

Thought so hope it goes well

Time has passed... The cats & O2 sensor replacements did the trick and we've put on another 21,000 trouble free miles since. I have a new *situation* for which I'll start a new thread but first I wanted to update this one and humbly thank those who replied to my plight(s). I am sooo grateful for the great tips y'all shared here which guided me through that unpleasant series of events. Thanks to this wonderful forum, I now have a history to share with the mechanics which will hopefully save some wear and tear on my last nerve. Y'all are DA BEST!!!

But I LOVE him Jerry wrote: ↑

Sun Aug 14, 2022 10:02 pm

Time has passed... The cats & O2 sensor replacements did the trick and we've put on another 21,000 trouble free miles since. I have a new *situation* for which I'll start a new thread but first I wanted to update this one and humbly thank those who replied to my plight(s). I am sooo grateful for the great tips y'all shared here which guided me through that unpleasant series of events. Thanks to this wonderful forum, I now have a history to share with the mechanics which will hopefully save some wear and tear on my last nerve. Y'all are DA BEST!!!

Thank you so much for updating us!
I am so glad previous issue was resolved!